Cytolytic activity of intestinal intraepithelial lymphocytes in germ-free mice is strain dependent and determined by T cells expressing gamma delta T-cell antigen receptors.

Abstract

We have compared the cytolytic activities and the cellular compositions of the inal lntraeplthellal lymphocyte (i-IEL) populations in three different combinations of conventional (CV) and germ-free (GF) mice. Cytolytic activity of i-EELs exps yS T-l antigen receptors (TCRs) b strain dependent in CV mice (high vs. low), and this straindependent variability b unaltered in the GF condition. Although absolute numbers of yv i-IELs are sightly decrased, the composition of CD8aa+ and CD4-CD8-subsets and the usage of TCR r and 8-chain variable gene segments by yS i-EELs remain the same in GF mice. By contrast, cytolytic activity of ar TCR-expressing i-JELs is uniformly high in CV mice but attenuated sharply in the GF condltion. A conspicuous decrease in the total numbers of afl i-IELs is also noted, and CD8rP+ and CD4+CD8+ subsets are reduced, whereas the CD8aa+ subset is expanded in GF mice. These rults indicate that microbial deprivation preferentially influences the a,B i-EEL population to decrease and become noncytolytic but has little effect on the pd size or characteristics of yS i-EELs. Consequently, cytolytic activity of feshly isolated i-KELs from GF mce b determined by T cellsexp ng y8TCRs and is found to be strin dependent.

Regional Phenotypic Specialization of Intraepithelial Lymphocytes in the Rat Intestine Does Not Depend on Microbial Colonization

“…This finding suggested that regional phenotypic specialization of IEL is an endogenous process, although an exogenous site-related effect of food antigens and dead bacteria in the autoclaved diet could not be excluded in the GF animals. However, the present study confirmed earlier observations that the introduction of a normal microbial flora causes a rapid expansion of TCRa/b þ IEL [9][10][11][12][13]. Despite this adoptive numeric response, which initially was most pronounced in the ileum (quicker establishment or higher load of gut bacteria?…”

“…Phenotypes of LCA þ IEL in the jejunum, ileum and colon of germ-free rats conventionalized (CV) for 1 week (CV 1 ) compared with agematched GF rats (GF 1 ), 5-week CV rats (CV 5 ), and 12-week CV rats (CV 12 ) compared with GF control rats (GF 12 ), as determined by two-colour in situ immunofluorescence staining. Proportions of IEL expressing TCRa/b, CD8a, CD8b, CD4 and CD5 were sigificantly increased in the ileum (P < 0.01) and those of TCRa/b and CD8a in the jejunum (P < 0.02) of CV 1 , whereas TCRa/b þ , CD8a þ and CD8b þ IEL were significantly increased both in the jejunum and the ileum (P < 0.01) in CV 12 compared with GF 1 and GF 12 , respectively. In the colon all T cell subpopulations examined had increased significantly in CV 1 , but no differences were noted between CV 12 and GF 12 rats.…”

Apoptosis of Villous Epithelial Cells and Follicle-Associated Epithelial Cells in Chicken Cecum.

“…In the mouse intestine, the existence of microbes increases the number of αβ IEL, but has little effect on γδ IELs [12]. In addition, it has been reported that the stimulation of intestinal bacterium accelerates the turnover of the epithelial cells in the intestine of rodents [1,3].…”

Differential Contribution of Fas- and Perforin-Mediated Mechanisms to the Cell-Mediated Cytotoxic Activity of Naive and In Vivo-Primed Intestinal Intraepithelial Lymphocytes

“…In mice the cellular composition of the IEL compartment varies greatly with age and conditions of maintenance (5,6). In general, the number of TCR␣␤ CD8␣␤ IELs increases with age and upon transfer of the mice from a germ-free environment to conventional conditions of maintenance, whereas the relative frequencies of TCR␥␦ IELs and CD8␣␣ IELs decrease under these conditions (7). Concomitant with the transfer of mice from germ-free to conventional conditions of maintenance, an increase in the constitutive cytotoxic activity of CD8␣␤ TCR␣␤ IELs is observed (5).…”